package day5;

import java.util.Scanner;

public class t4 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("请输入圆的半径：");
        int r=sc.nextInt();
        S_calculate(r);
    }

    public static void S_calculate(int r) {
        double S = 3.14*r*r;
         System.out.print("请输入圆的面积为："+S);
    }
}
